On facial recognition

Hehe, so I have a plan for a new quiz for you all. Below you'll see 10 images. They're well known duos, and I've been photoshopping them. I've taken the head of one, and pasted the face of the other into it. See if you can guess who the duos are...

Image 1. Easy Peasy...

Image 2. The kings of Saturday night TV

Image 3. Slightly disturbing. He has been known to wear her clothes or make up.

Image 4. No really, I have changed this one.

Image 5. Ok, so this is really starting to get hard.

Image 6. This looks quite normal.

Image 7. The former kings of Saturday night.

Image 8. Let's not make a song and dance about it.

Image 9. Now I think this is hard, and I made it!

Image 10. I don't think anyone will get this.

Answers as normal in the comments. Good Luck.